Retaining walls and parapets are two common types of walls which can be constructed using segmental wall blocks. Retaining walls are commonly employed to retain highly positioned soil, such as soil forming a hill, to provide a usable level surface therebelow such as for playgrounds and yards, or to provide artificial contouring of the landscape which is aesthetically pleasant. Parapets, on the other hand, are free standing walls having two exposed sides which, in some cases, may be located directly on top of retaining walls or other structures.
Retaining walls and parapets have been made of concrete blocks having various configurations, the blocks generally being stacked one atop another. Retaining wall blocks are generally stacked against an earthen embankment with the wall formed by the blocks extending vertically or being formed with a setback. Setback is generally considered to be the distance in which one course of a wall extends beyond the front of the next highest course of the same wall. Parapets blocks are generally stacked in a single stack, or in a pair of stacks separated by a small but variable distance, which may be filled and generally are stacked without a setback. Concrete blocks have been used to create a wide variety of mortared and mortarless walls. Such blocks are often produced with a generally flat rectangular surface for placement onto the ground or other bearing foundation and for placement onto lower blocks in erecting the wall. Such blocks are also often further characterized by a frontal flat or decoratable surface and a flat planar top for receiving and bearing the next course of blocks forming the wall.
It is generally desired that walls of the type described exhibit certain favorable characteristics, including the ease with which the wall can be assembled, the stability of the wall (that is, its ability to maintain structural integrity for long periods of time), and the ability of the wall to admit and disburse rainwater. Although segmental wall blocks commonly are supported vertically by resting upon each other, in the case of retaining walls, it is important that the blocks be restrained from moving outwardly from the earthen wall that they support. In the case of parapets, it is important that the wall be stable if the surface on which the parapet rests, such as the ground or a retaining wall, shifts, and that the parapet be able to withstand impacts or other forces pressing against it.
Current manufacturing techniques and the economics associated therewith limit the shapes, sizes, and materials that may be used to manufacture blocks that still provide the functions described above. In some instances, it would be preferred to make blocks in different shapes, sizes, and colors, and using different quality, types, and price of materials, and possibly in a centralized location which may be further from their point of use. Accordingly, the segmented retaining wall blocks must be transported to the installation location. When segmented wall blocks are transported to the installation location, they are typically stacked on a pallet for easier transportation. Blocks or block components that do not stack evenly can result in stacks that are not of uniform size. For instance, one row may lean heavily in a particular direction. This risks having the shipment not fit in or on its transporting vehicle. Of greater concern, though, are that blocks that do not stack evenly may be less stable than desired.